薇甘菊(Mikania micrantha)是华南地区危害最严重的外来入侵杂草, 对天然次生林及其他生境造成了极大危害。为了探明本地植物粉葛(Pueraria lobata var. thomsonii)对薇甘菊进行替代控制的可能性, 本实验设置了3个水分水平(土壤含水量低于10%、60-70%和120-130%)分别模拟干旱、正常水分(对照)和涝害, 比较了粉葛与薇甘菊对干旱和涝害胁迫的生理响应差异。结果表明, 在干旱胁迫条件下, 薇甘菊的总生物量显著降低, 为对照的72%。在涝害胁迫条件下, 粉葛的总生物量与对照相比上升了16%, 薇甘菊则下降了15%。在干旱条件下, 粉葛的根冠比、叶绿素含量均显著高于对照(P < 0.05), 恢复正常水分后仍维持在较高水平; 薇甘菊的根冠比则与对照无显著差异(P > 0.05), 仅叶绿素含量显著高于对照(P < 0.05), 在恢复正常水分后低于正常水平。这可能与粉葛体内积累了较多的渗透调节物质脯氨酸和可溶性糖有关。在涝害条件下, 粉葛的丙二醛(malondialdehyde, MDA)含量约为对照的2.1倍, 薇甘菊则为对照的3.0倍; 恢复正常水平后, 薇甘菊和粉葛的MDA含量仍维持在较高水平, 分别为对照组的1.72倍和1.45倍, 显示粉葛受涝害影响的膜脂过氧化水平低于薇甘菊。可见, 粉葛比薇甘菊有更强的抗干旱能力和抗涝害能力, 对水分胁迫有更强的抗逆性, 抵抗力指数也印证了这一点。这为选用粉葛对华南地区天然次生林林缘或林窗生境薇甘菊的替代控制提供了理论支持。

Mikania micrantha is the most dangerous invasive weed in South China, due to its harmful effects on natural secondary forest habitats and other habitats. In order to illustrate the possibility of using the native legume Pueraria lobata var. thomsonii to replace M. micrantha, three water gradients (soil water content < 10%, 60-70% and 120-130%) that simulate drought, normal soil water content (as control) and waterlogged conditions, respectively, were established to study the physiological response of these two plant species to drought and waterlogging. Results showed that under drought stress, the total biomass of M. micrantha decreased significantly by 72% as compared to controls. Under waterlogging stress, the total biomass of P. lobata var. thomsonii increased by 16% compared to the control treatment, while M. micrantha decreased by 15%. Under drought conditions, the root-shoot ratio and chlorophyll content of native species P. lobata var. thomsonii were significantly greater than those found in the control (P < 0.05); while there were no significant differences in the root-shoot ratio of M. micrantha compared to the control (P > 0.05), but the chlorophyll content was significantly higher than that found in the control but lower than the normal level after rewatering. This may be the result of a significant increase in the proline and soluble sugar in P. lobata var. thomsonii. Following waterlogging stress, the malondialdehyde content of P. lobata var. thomsonii was approximately 2.1 times higher than the control, while that of M. micrantha was 3 times the control. After soil water content returned to normal levels, the malondialdehyde content of M. micrantha and P. lobata var. thomsonii maintained high levels, which were 1.72 times and 1.45 times the control group, respectively, indicating that the membrane lipid peroxidation level of P. lobata var. thomsonii was lower than that of M. micrantha as affected by waterlogging. Thus, it was concluded that P. lobata var. thomsonii exhibited better drought and waterlogging tolerance than M. micrantha. The resistance index also confirmed this conclusion. The results provide theoretical support for the control of M. micrantha through replacement by applying the native legume P. lobata var. thomsonii to natural habitats like forest edges or windows in areas of South China.